Pipeline

Abstract

A pipeline for use in the offshore production of hydrocarbons comprising: (i) an electrically conductive inner pipe, (ii) a concentric outer layer, (iii) one or more concentric intermediate layers between the inner pipe and the outer layer, and (iv) a concentric electrically conductive mesh. A simple and usually thin mesh allows electric heating along the inner pipe with easy manufacture, and therefore significantly increases the simplicity and efficiency of the electrical heating of the pipeline.

1 . A pipeline for use in the offshore production of hydrocarbons comprising:
 (i) an electrically conductive inner pipe,   (ii) a concentric outer layer,   (iii) one or more concentric intermediate layers between the inner pipe and the outer layer; and   (iv) a concentric electrically conductive mesh.   
     
     
         2 . A pipeline as claimed in  claim 1 , wherein the conductive mesh is around or within at least one of the intermediate layers or the outer layer. 
     
     
         3 . A pipeline as claimed in  claim 1 , wherein at least one of the intermediate layers is an insulation layer. 
     
     
         4 . A pipeline as claimed in  3 , wherein the conductive mesh is embedded within an intermediate insulation layer. 
     
     
         5 . A pipeline as claimed in  claim 1 , wherein at least one of the intermediate layers is a thermal insulation layer. 
     
     
         6 . A pipeline as claimed in  claim 1 , wherein the conductive mesh is formed from copper. 
     
     
         7 . A pipeline as claimed in  claim 1 , wherein the conductive mesh is in the range 1-5 mm thick, preferably 2 mm thick. 
     
     
         8 . A pipeline as claimed in  claim 1 , wherein the pipeline is a pipe-in-pipe flowline. 
     
     
         9 . A system for electrically heating a pipeline comprising:
 a pipeline according to  claim 1  having an electrically conductive inner pipe and a concentric electrically conductive mesh;   at least one electrical current pathway between the inner pipe and the conductive mesh;   a power input connected to the inner pipe; and   a current return connected to the conductive mesh to receive current from the power input, inner pipe and electrical current pathway.   
     
     
         10 . A method of electrically heating a pipeline comprising:
 passing current from a power input along an electrically conductive inner pipe of a pipeline according to  claim 1 ;   passing the current from the inner pipe along at least one electrical current pathway to a concentric electrically conductive mesh; and   passing current along the conductive mesh to a current return.   
     
     
         11 . (canceled)